1. Field of the Invention
The present invention relates to fatty acid esters of alkoxylated isethionic acid and specifically to compositions comprising the fatty acid esters.
2. Prior Art
The use of alkoxylated isethionates having the formula
R-(OCH.sub.2 CH.sub.2).sub.n SO.sub.3.sup.- Na.sup.+
is known in the art, for example, from U.S. Pat. No. 3,823,185 to Schlossman.
The use of fatty acid esters of isethionate, e.g., sodium cocoyl isethionate having the formula ##STR1##
is also known in the art (see for example, Rys et al., U.S. Pat. No. 4,954,282).
U.S. Pat. No. 3,029,264 to Alphen et al. teach compounds of formula RCOOR'SO.sub.3 M. To the extent R' may be a dialkylene ether radical as disclosed at column 2, line 34, the reference, at least in theory, discloses fatty acid esters of a monoethoxylated isethionate. Although it is stated at column 3, lines 21-23, that products of the invention can be used to make detergent tablets, it is clear from the reference that none of the compounds made were ethoxylated isethionates (see Examples 1-9) and it is further clear that none of the compounds were formulated in any event (there are no formulation examples). Thus, the reference clearly fails to recognize that ethoxylated isethionates can be made or that, if made, they might have any advantages, i.e, formulation advantages, over their non-ethoxylated counterparts.
British Patent No. 974,124 (Shell) teaches compounds at column 1, line 3, where, if x is zero and n is 2, the compound may be diethoxylated. However, the R group is a secondary or tertiary carbon CR.sub.1 R.sub.2 R.sub.3 which differs from the compounds of the invention. Further, there is no recognition of the specific formulation advantages of the diethoxy compound.